In U.S. Pat. No. 4,198,032 granted Apr. 15, 1980, a bottom operated tank car lading valve is disclosed which is operated by means of an operating shaft extending downwardly below the tank bottom. The operating shaft is provided with a cap. To open or close the lading valve, the cap is removed and a suitable operating tool is attached to a lower nonround end of the operating shaft. However, this arrangement is undesirable because only tools having a nonround opening may be utilized to operate the shaft. Thus, pinch bars and ratchet extensions cannot readily be utilized in this arrangement.
In U.S. Pat. No. 4,212,447 granted July 15, 1980, a captive handle assembly is disclosed for rotating the operating shaft connected to the bottom outlet valve. The handle is pivotably mounted adjacent the lower end of the operating shaft and the distal end is removably mounted adjacent the tank bottom. In use, the handle is pivoted nearly 90.degree. and is used to rotate the operating shaft and move the lading valve between open and closed positions. In one embodiment, a nonround handle portion is in continuous engagement with the operating shaft. In another embodiment, the handle portion is moved longitudinally to achieve engagement with the operating shaft. In a third embodiment, the handle includes a ratchet assembly which is in continuous engagement with the operating shaft.
However, these captive handle assemblies are expensive. Customers resist the added cost and point out that they have available in the yard a variety of suitable tools such as pinch bars and ratchets, and therefore do not wish to pay the added cost of a captive handle.